Well the upgrade junky geek part of me knows its crappy advice to recommend 939 these days, but the dfi rs482 has dvi-d build in. And afaik dvi can be converted to hdmi, so hdmi from onboard is possible with that board. (then use the spdif to reciever to get your dolby audio)
Sure ddr1 ram is passe, and 939 is a dead socket, but HTPCs don't usually follow the same uber-geek principles as other systems. I don't think anybody I've built a HTPC for ever maxed out the cpu, so core2 isn't a required element, no matter how cool it is.
Atleast the 939 single core chips aren't as warm as their priced Intel competition.
I always try and keep my designs on 'live' tech, but htpc is one place I don't mind selling the 'old stuff'.